On the electricity network connection at the output of a farm of electricity generating machines such as wind turbines, a “voltage dip” may occur, which consists of a brusque decrease in voltage as a result of faults on the network, which causes a dip zone or constant decrease in voltage and a swell zone with increasing voltage once the fault which caused the dip is resolved, both of which have a determined duration depending on the voltage dip that occurred. Due to the technical requirements of the network, during the voltage dip a time variable injection of the reactive current required by the machines is needed, in order to contribute toward re-establishing the voltage and reducing the affects of said dip.
In this sense, the regulatory bodies for electrical networks define curves which determine the value of the reactive current that should be injected onto the network during the voltage dip. These curves give a reactive current value according to the depth of the detected dip.
In this technique there are known devices with which reactive current is permanently injected at a variable setting which can be changed in time frames of minutes or seconds.
With such devices however, the reactive current to be injected cannot be adapted to the variable network voltage in very short periods of time. In addition, the known devices are designed with overload capacities limited to two or three times their nominal capacities, which makes their application with high current economically impractical.
This invention is focused on providing a solution to this problem.